Method for controlling a headlight

ABSTRACT

The invention relates to a method for controlling a light distribution of a headlight, in particular of a headlight comprising one illuminant or comprising a plurality of illuminants which generates or generate an adaptable light distribution, wherein a glare region of the light distribution is defined with a glare distance outside which no causing of glare for a road user is effected, wherein an optical monitoring device having a monitoring region having a monitoring boundary is provided, wherein a luminous object is identifiable as a road user only within the monitoring region, wherein upon recognition or supposition of at least one luminous object which is outside the monitoring region but within the glare region, the at least one headlight is driven such that the glare distance is adapted, such as in particular reduced.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is based upon and claims the benefit of priority fromprior German Patent Application No. 10 2015 214 760.6, filed Aug. 3,2015, the entire contents of which are incorporated herein by referencein their entirety.

TECHNICAL FIELD

The invention relates to a method for controlling a headlight, inparticular for controlling one headlight or two headlights or headlightsystems of a motor vehicle.

PRIOR ART

Modern headlights for motor vehicles are becoming better and better,that is to say that the light intensity of the headlights is increasingmore and more. This has the effect that the maximum range of the lightdistribution is increasing further and further and the intensitydistribution can thus also extend further and further in front of themotor vehicle, which also causes the maximum glare distance of theheadlight to increase. In this case, the glare distance is the distancewhose limit indicates where the undershooting occurs of an intensitythreshold value for which an unreasonable glare effect on other roadusers no longer takes place. If an object is situated nearer to theheadlight than the glare distance, then an unreasonable glare effectwould possibly occur. At a distance that is further than the glaredistance, a glare effect would possibly occur, but it may be regarded asreasonable. The glare distance is dependent here on the angle of theobject with respect to the headlight.

The increase in the maximum range means that in modern headlights theremay be the risk of glare even at a relatively great distance from themotor vehicle if another road user were situated within the glaredistance of the headlight. In the prior art, optical monitoring devicesare known which can monitor a monitoring region in front of the motorvehicle, such that other, in particular oncoming, road users in themonitoring region can be recognized and identified and their distance orposition with respect to the own motor vehicle can be determined. Inthis regard, the light distribution of the headlight can be controlleddepending on the other road users recognized, in order not to subjectthem to glare, that is to say to suppress glare for them.

However, the modern headlights in the meantime have attained a rangethat is significantly greater than the range of the monitoring region ofa conventional monitoring device in the prior art. As a result, inparticular oncoming road users may be subjected to glare far earlierthan they can be identified as road users by the optical monitoringdevices available today.

U.S. Pat. No. 5,837,994 discloses an automatically controllable vehicleheadlight wherein an optical monitoring device recognizes front lightsor rear lights and can differentiate them, such that other motorvehicles can be recognized, and the headlight is controlled in such away that the high beam is controlled as a function of the distance andthe horizontal orientation relative to the own motor vehicle. In thiscase, it thus becomes clear that the monitoring device can identify thelights of other road users as such in the monitoring region and can thusalso identify the other road users as such. This also means that therange of the headlight and in particular the glare distance thereofcorrespond to or even undershoot the range of the monitoring region, asalready explained above. Modern headlights, by contrast, have a farhigher range and glare distance in comparison therewith, such that thisrecognition of the road users for whom glare is to be suppressed cannotbe carried out.

SUMMARY OF THE INVENTION, PROBLEM, SOLUTION, ADVANTAGES

Therefore, the problem addressed by the invention is that of providing amethod for controlling a headlight which can be carried out in a simplemanner but nevertheless allows reliable suppression of glare foroncoming road users. Moreover, the intention is to provide a motorvehicle for carrying out such a method.

The problem addressed by the invention concerning the method is solvedby the features of Claim 1.

One exemplary embodiment of the invention relates to a method forcontrolling a light distribution of a headlight, in particular of aheadlight comprising one illuminant or comprising a plurality ofilluminants which generates or generate an adaptable light distribution,wherein a glare region of the light distribution is defined with a glaredistance outside which no causing of glare for a road user is effected,wherein an optical monitoring device having a monitoring region having adelimited monitoring range or having a monitoring boundary is provided,wherein a luminous object is identifiable as a road user only within themonitoring region, wherein upon recognition or supposition of at leastone luminous object which is outside the monitoring region but withinthe glare region, the at least one headlight is driven such that theglare distance is adapted, such as in particular reduced. What isachieved as a result is that upon recognition of at least one objectoutside the monitoring region glare is intended to be adapted or reducedor even avoided. This provides for improved safety for road users atrisk of glare in particular even with the use of modern headlights.

In the case of a headlight comprising a plurality of illuminants, thismay involve illuminants that are integrated into a housing, orilluminants that each have a dedicated housing. A headlight isoptionally characterized in that the light distributions of theindividual illuminants are superimposed to form a total lightdistribution. A road user is furthermore taken to mean an object at riskof glare, in particular a motor vehicle comprising at least oneself-luminous element that is controlled by a road user. This mayadvantageously involve a motor vehicle, in particular an oncoming motorvehicle comprising two visible, self-luminous front headlights. Theobject may likewise be an oncoming two-wheeler comprising one visibleluminous element, that is to say one headlight.

It is advantageous here if the delimited monitoring range or themonitoring boundary is determined such that other, in particularoncoming, road users in the monitoring region can be recognized andidentified and their distance or position with respect to the own motorvehicle can be determined. It is particularly advantageous here ifother, in particular oncoming, road users, by the time they enter themonitoring region, can be reliably recognized and identified and theirdistance or position with respect to the own motor vehicle can bedetermined.

It is thus advantageous here if the monitoring boundary of themonitoring region is determined by determining the visual range of thecamera and subtracting therefrom the distance covered by the objectuntil it is identifiable as a road user. Here the visual range of thecamera is the distance at which a luminous object can be recognized. Thedistance covered until identification as a road user is determined heredepending on the relative speed of the object and depending on therecognition time required at the distance.

Therefore, it is advantageous if the monitoring boundary of themonitoring region is determined depending on at least one of thefollowing conditions: visibility conditions, weather conditions, maximumpermissible speed, in particular from the section being driven along atthis point in time, current speed of the motor vehicle and/or object andthe course of the section of roadway.

Furthermore, it is advantageous if the glare region is the maximum glareregion of the headlight, and if the glare distance designates thecurrent glare distance of the headlight.

It is particularly advantageous if the glare distance is reduced if theglare region is set to be larger than the monitoring region, inparticular if the glare region corresponds to the maximum glare region.

Moreover, it is expedient if the glare distance remains unchanged or isincreased if the glare region is set to be smaller than the monitoringregion or in a manner corresponding to the monitoring region. Moreover,it is advantageous if the adaptation, such as in particular thereduction, of the glare distance of the at least one headlight iseffected on the basis of a residence probability of the object or of theluminous object. In this case, the residence probability is determinedfor the object, and a lower limit for the distance of the object isdetermined therefrom in order to be able to expediently reduce the glaredistance or set it to a reduced value.

It is therefore advantageous here if the glare distance is reduced tothe lower limit of the distance of the object for which the glaredistance is reduced on the basis of the residence probability.

Furthermore, it is advantageous if the glare distance is reduced on thebasis of a residence probability of the object or of the luminous objectin such a way that the glare distance is in particular precisely withinthe monitoring region. It can be ensured in this way that an objectoutside the monitoring region cannot be subjected to glare by theheadlight.

It is particularly advantageous here if for reducing the glare regionand/or the glare distance, the intensity of the light of the headlightis reduced. A simple driving of the headlight or of at least one of itsilluminants can be performed as a result.

Moreover, it is expedient if the intensity of the light of the headlightis reduced in a predefined areal or spatial region, such that the glaredistance is reduced in a predefined areal or spatial region, inparticular in front of a motor vehicle. As a result, local suppressionsof glare can be performed, wherein no suppression of glare is performedin other areal or spatial regions. The suppression of glare performedmay be configured dynamically with respect to time here in order, ifappropriate, to comply with a moving object and to suppress glare forthe latter. It is advantageous here if the areal or spatial region forwhich glare is suppressed corresponds to that in which a residenceprobability higher than a predefined threshold value is present.

It is also advantageous here if the residence probability of the objector of the luminous object outside the monitoring region and within theglare region is determined. A probability of an object or a luminousobject being situated outside the monitoring region and within the glareregion is thus determined. As a result, the location of the object isestimated, such that the suppression of glare can be performed on thebasis of this residence probability determined, if it is assumed thatglare is to be suppressed for the object. Furthermore, it isadvantageous, particularly with a reduced glare distance, to determinethe probability of whether an object is situated outside the monitoringregion, but within the maximum glare region.

Moreover, it is advantageous if the residence probability of the objector of the luminous object is determined on the basis of the data of themonitoring device. In this case, on account of the light intensity orthe pattern on the basis of available background data of different typesof headlight, an object can be assumed which could generate acorresponding image, such as the image recorded by the monitoringdevice.

Moreover, it is advantageous if the residence probability of the objector of the luminous object is composed of the probability of the objector of the luminous object being an object at risk of glare and/or theprobability of the object at risk of glare being situated in the glareregion of the headlight and/or the probability of an object beingpresent. Alternatively or additionally, the residence probability iscomposed of the probability of the object or the luminous object beingan object at risk of glare and/or the probability of the object at riskof glare being situated in the illumination region of the headlight,wherein the illumination region is composed of the monitoring region,the glare region and a region in front of the glare region in which noglare takes place. Object at risk of glare is advantageously taken tomean another road user, in particular another road user controlling amotor vehicle comprising at least one headlight. The glare region or theillumination region is taken to mean in particular the maximum glareregion or illumination region of the headlight. In one advantageousdevelopment, the current glare region or illumination region can beused. It is advantageous here to carry out the method only if thecurrent glare region of the headlight exceeds the current monitoringregion of the monitoring device. Otherwise a conventional method isintended to be used.

Moreover, in one exemplary embodiment it is advantageous if during thereduction of the intensity of the light of the headlight, the intensityprofile of the light of the object is used for classifying the luminousobject. As a result, it is possible to differentiate whether the objectis a self-luminous object or an irradiated object. The self-luminousobject does not change its intensity profile, while the irradiatedobject also varies its intensity profile. An irradiated object is takento mean in particular an object which becomes a luminous object only bymeans of irradiation by another light source. In particular, this istaken to mean an object having a surface which reflects the light in awavelength range identical or at least similar to the incidentwavelength range, in particular an object having at least one reflector.It is advantageous here if the fact of whether the object is aself-luminous object or an irradiated object is used for identifying anobject as a road user.

Furthermore, it is advantageous if the object is classified on the basisof a temporal pattern generated by the headlight. In this case, inaddition to the first dimming, the headlight advantageously performsfurther dimmings which are preferably effected successively in apredefined temporal sequence. It is furthermore advantageous if thesetemporal sequences are created randomly and made available for theclassification. It is furthermore advantageous if the further dimmingsare effected such that they are not perceived by the driver. This may bedone in such a way that the plurality of dimmings are carried out oneafter another very rapidly in time and/or that these dimmings areeffected within a very small intensity range. As a result, the intensityvariation observed with the aid of the monitoring unit at the object tobe classified can be associated unambiguously with the headlight and aself-luminous object can be ruled out even more reliably.

Moreover, it is advantageous if the glare region of the headlight isdivided into a safe zone and into a comfort zone, wherein no damage tothe eye and no serious visual restrictions are present in the safe zoneand no glare effect is present in the comfort zone. As a result, theobject can be irradiated in such a way that it is either in the safezone or in the comfort zone if it passes into the glare region. No glareeffect means that only a reasonable glare effect for another road useris generated in the eye.

Moreover, it is advantageous if the reduction of the glare region in thecase of residence probabilities below a threshold value is effected insuch a way that the object is situated at least in the safe zone. Thereduction here means the reduction of the glare distance.

It is particularly advantageous if the reduction given the presence of aresidence probability above a threshold value is effected in such a waythat the object is situated at least in the comfort zone. In thisregard, a location assumed to be probable is extracted from theresidence probability for the object, said location being taken intoaccount in the control.

In this regard, it is also advantageous if in the case of an unsafedistance determination for the object, the glare region of the headlightis reduced in such a way that all objects are situated at least in asafe zone.

Moreover, it is advantageous if the light intensity is reduced in aregion having increased brightness compared with the surroundingdistribution. As a result, the reduction is perceived less distinctly bythe driver and a disturbance of the driver can be reduced or evenavoided.

Moreover, it is advantageous if the reduction of the light intensity isachieved by reducing or switching off superimposing light sources orlight distributions which are used for generating a matrix high beamand/or which lie in the region in which at least one additionalspotlight or additional spotlights is or are superimposed on the matrixhigh beam and/or lies or lie in a region centrally with respect to thematrix high beam. In this regard, the luminous distance or the glaredistance is reduced by the light intensity of specific selectedilluminants being reduced in a targeted manner.

Moreover, it is advantageous if an object is regarded as notclassifiable or as not identifiable as a road user if the classificationmethod yields no result or yields no result with sufficient quality oryields no result in a predefined time period or the classificationmethod yields no result by the time a predefined distance of the objectis undershot, or if a method for preclassification yields no result oryields no result with sufficiently good quality. If no classification ispresent, it is advantageous if the object is regarded as an object forwhich glare is to be suppressed. Increased safety is generated as aresult. An object can be identified as a road user if it isclassifiable. A result of sufficiently good quality is present if theclassification quality and/or the probability of the classificationbeing correct exceed(s) a predefined threshold value. In particular, anobject can be identified as a road user if it is classifiable untilreaching a predefined minimum distance. A result of sufficiently goodquality is therefore present if the classification quality and/or theprobability of the classification being correct attain(s) a predefinedthreshold value until reaching a predefined distance of the object fromthe headlight or the motor vehicle.

Moreover, it is advantageous if the glare region or the illuminationregion is extended if the probability of an object at risk of glarebeing situated outside the monitoring region decreases or becomes zeroor falls below a threshold value. In this regard, the glare distance isincreased again if no object is situated in the glare region withmeaningful residence probability and, correspondingly, very probably noglare is effected. In particular, this is possible if a classificationwas able to be improved on the basis of the observation of the intensityprofile, such that a classification result with sufficiently goodquality can be generated. In this way, an object can be classifiedreliably as even before entering the monitoring region.

It is particularly advantageous here if the reduction of the lightdistribution is reversed by the superimposing light distribution beingswitched on again, in particular switched on in a stepwise manner. Thereversal can be effected slowly here, in particular more slowly than theperformance of the reduction itself.

Moreover, it is advantageous if the glare region or the illuminationzone is reduced given the presence of a glare probability, wherein theglare region or the illumination zone is reduced or shortened whenobjects are present outside the classification range, and/or the glareregion or the illumination zone is reduced or shortened whennon-classifiable objects are present, and/or the glare region or theillumination zone is reduced or shortened when non-visible regions aredetected.

The problem is also solved by a method for controlling a lightdistribution of a headlight, in particular of a headlight comprising oneilluminant or comprising a plurality of illuminants which generates orgenerate an adaptable light distribution, wherein a glare region of thelight distribution is defined with a glare distance outside which nocausing of glare for a road user is effected, wherein an opticalmonitoring device having a monitoring region having a monitoringboundary is provided, wherein an object is identifiable as a road useronly within the monitoring region, wherein upon recognition of an objectwhich might be a road user or upon supposition of a road user, whichobject or which road user is outside the monitoring region but withinthe glare region, the at least one headlight is driven such that theglare distance is reduced.

It is also advantageous here if the residence probability of arecognized object and/or of a supposed road user outside the monitoringregion and within the glare region is determined.

A road user here is taken to mean an object at risk of glare, inparticular a motor vehicle controlled by a road user. This mayadvantageously involve a motor vehicle, in particular an oncoming motorvehicle. The object may likewise be an oncoming two-wheeler or anoncoming pedestrian. Oncoming two-wheelers and/or pedestrians areadvantageously recognized here on the basis of at least one vehiclesensor system, in particular on the basis of lidar, radar or infraredbeams or on the basis of vehicle-to-two-wheeler/pedestrian communicationsystems.

It is thus advantageous here if the monitoring boundary of themonitoring region is determined by determining the visual range of thevehicle sensor system used and subtracting therefrom the distancecovered by the object until it is identifiable as a road user. Here thevisual range of the vehicle sensor system used is the distance at whichan object can be recognized. The distance covered until identificationas a road user is determined here depending on the relative speed of theobject and depending on the recognition time required at the distance.The problem addressed concerning the motor vehicle is solved by thefeatures of Claim 24.

One exemplary embodiment relates to a motor vehicle comprising at leastone headlight, advantageously comprising two headlights, and comprisingan optical monitoring device for carrying out a method according to theinvention.

Further advantageous configurations are described by the followingdescription of the figures and by the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail below on the basis of atleast one exemplary embodiment with reference to the figures of thedrawing, in which:

FIG. 1 shows a schematic illustration of a motor vehicle comprising atleast one headlight having a first and a second light distribution,

FIG. 2 shows a schematic illustration of a light distribution of aconventional headlight with high beam,

FIG. 3 shows a schematic illustration of a light distribution of amodern headlight having high beam and having a high-intensity beam,

FIG. 4 shows a schematic illustration of a brightness distribution, and

FIG. 5 shows a schematic illustration of a light distribution of a lowbeam,

FIG. 6 shows a schematic illustration of a light distribution of a highbeam,

FIG. 7 shows a schematic illustration of a light distribution of ahigh-intensity beam,

FIG. 8 shows a schematic illustration of a light distribution of a highbeam with high-intensity beam,

FIG. 9 shows a schematic illustration for elucidating suppression ofglare in the case of a non-classifiable object,

FIG. 10 shows a schematic illustration for elucidating suppression ofglare in the case of an object classified as a reflector, and

FIG. 11 shows a schematic illustration for elucidating suppression ofglare in the case of an object classified as a motor vehicle.

PREFERRED EMBODIMENT OF THE INVENTION

FIG. 1 shows in a schematic illustration a first light distribution 1 ofa headlight according to the prior art, see left, and a second lightdistribution 2 of a high beam of modern headlights, see right.

It is evident that the first light distribution 1 has a significantlyless expansive range and the glare distance 3 constitutes a knowndistance. In this case, the headlight according to the prior art underconsideration is mounted for example on the motor vehicle 4. In thiscase, for controlling the headlight, the motor vehicle 4 comprises anoptical monitoring device, the monitoring region of which substantiallyhas the range of the glare distance 3 of the headlight, such that theregion in front of the motor vehicle 4 that is monitored for other roadusers covers the region at risk of glare from the headlight. Anotherroad user can therefore be discovered and identified as such beforebeing subjected to glare, and in such a case the headlight can becontrolled in such a way that glare is suppressed for the other roaduser.

With the higher illuminances of the modern headlights, by contrast,significantly greater ranges and thus also greater glare distances 5 canbe achieved, as revealed by the light distribution 2 of a modernheadlight. Another, for example oncoming, road user 6 not yet subjectedto glare in the case of a headlight according to the prior art is nowsubjected to glare with the use of modern headlights on account of thehigher glare distance 5. Since other road users 7 at a greater distancemay also already be subjected to glare, this necessitates asignificantly higher observation distance of an optical monitoringdevice at which a luminous object is identifiable as a road user, thatis to say that a distinction can be made between the monitored object asanother road user for whom glare is to be suppressed and an object forwhich glare does not have to be suppressed. This is relevant becauseotherwise a suppression of glare would take place for other luminousobjects as well, which would be undesirable, however. This is becausefor example irradiated, that is to say reflective, objects, such as inparticular retroreflective elements on reflector posts, are oftenemployed in proximity to roads and are in the main difficult todifferentiate from objects for which glare is to be suppressed.Non-differentiation would either cause the headlight to repeatedlyswitch to high beam and low beam in an unjustified manner or, as aresult of excessively long dimming, make it impossible to use the greatluminous distance for better vision. In this regard, for example,traffic signs or retroreflective objects, that is to say reflectors orthe like, may be illuminated, which are then recognizable as luminousobjects even at relatively great distances from the own motor vehicle,wherein it is not possible to recognize whether this involves anotherroad user or non-relevant other objects. Such other objects areillustrated as traffic signs 8, for example, in FIG. 1.

Therefore, if the glare distance 5 of the modern headlights increasessignificantly, such as by +70%, for example, even non-relevant objects,such as traffic signs, for example, even at significantly greaterdistances, such as by 30% or more, for example, may be recognizable asluminous objects. In particular, this is the case if a retroreflectiveobject is illuminated by a light source such as, in particular, theheadlight of the motor vehicle 4 with high intensity and is thusmanifested as a bright object to the optical monitoring device.

However, since the optical monitoring devices cannot accomplishdiscriminative recognition at the greater distances, the risk ofincorrect decisions in the control of the suppression of glareincreases.

The method according to the invention for controlling a lightdistribution of a headlight provides for the headlight to comprise atleast one illuminant or a plurality of illuminants which can be driven.The illuminant or the illuminants generate(s) an adaptable lightdistribution, wherein a glare region of the light distribution isdefined with a glare distance 5 outside which no causing of glare for aroad user is effected, wherein an optical monitoring device having amonitoring region 9, in particular having a monitoring boundary orhaving a delimited monitoring range is provided, wherein a luminousobject is identifiable as a road user only within the monitoring region.In this case, upon recognition or supposition of a luminous object 7, 8which is outside the monitoring region but within the glare region, theat least one headlight is driven, such that the glare distance isreduced and the glare is reduced or glare is suppressed for the object.

In this case, the glare distance 5 of the at least one headlight isreduced on the basis of a residence probability of the luminous object7, 8.

In this case, the monitoring region of the monitoring device isdescribed or defined for example in this way: the monitoring region is azone in which road users, that is to say objects, at risk of glare canbe recognized and classified with high reliability and their distancecan be downwardly delimited. In this case, the monitoring region is alsoadvantageously a zone in which road users, that is to say objects, atrisk of glare, by the time they enter said zone, can be recognized andclassified with high reliability and their distance can be downwardlydelimited. For this purpose, it is therefore necessary to be ablealready to recognize the object beforehand and to classify it with highreliability even at high speed within a time period dependent thereon.By way of example, a classification and/or detection means of thevehicle sensor system is used for determining the object. On the basisof the classification result, the distance of the object is thendetermined and/or downwardly delimited. The zone can be preset ordetected and/or updated on the basis of the determination ofsituation-dependent classification probabilities and probabilities forthe position and/or distance of an object in the surroundings. In thiscase, the surroundings, in particular the course of the roadway beingdriven along, such as a horizontal and/or vertical curvature, can bedetermined and taken into account. Furthermore, visibility and weatherconditions can affect the size of the zone and can be concomitantly usedimplicitly or explicitly for the determination.

Outside the monitoring region of the monitoring device, although anobject may possibly still be recognized as a luminous object, it is notpossible to identify it with certainty as a road user. In particular, itis not possible to do this with certainty before the object enters themonitoring region. However, in order not to endanger the other road userby glare, a decision about suppression of glare must be taken, however,actually before entry into the glare region or within a predefined timeperiod. For this purpose, a residence probability is determined for eachrecognized luminous object, the headlight being driven depending on saidresidence probability.

In addition, other sensor data, such as, in particular, radio data, orother car-to-X data or statistical data, for example from a memory, canbe used for determining the residence probability. This is also possibleas an alternative to the monitoring device if, outside the monitoringregion of the monitoring device, another road user cannot be recognizedas a luminous object. This may be the case for example on account of apresent vertical and/or horizontal curvature of the course of theroadway being driven along. This is because the monitoring region hasmaximally a monitoring boundary of the visual range of the camera minusthe distance covered by the object in the recognition time.

In this case, the residence probability is described or defined in thisway: the residence probability is a probability of an object beingsituated outside the monitoring region but within the glare region. Theresidence probability is determined on the basis of the sensor data andis composed, for example, of the probability of an object at risk ofglare being involved and/or the probability of the object at risk ofglare being situated in the glare region or in the illumination regionof the headlight and/or the probability of an object at risk of glarebeing present.

In this case, particularly upon the recognition of a luminous object,the probability of the latter being situated within the glare region canbe determined under the assumption that said object is a road user, thatis to say an object at risk of glare. An algorithm can be used for thiscalculation, which algorithm is also used for the determination and/orlower limitation of the distance of a luminous object identified withhigh certainty as a road user. In the case where the object is not aroad user, this distance determination would not yield a correct result.Therefore, the probability of the recognized object being a road user isto be concomitantly used in the determination of the residenceprobability. It is advantageous here to carry out a distancedetermination under the assumption that the luminous object is a roaduser for every image or for every n-th image as soon as the luminousobject is recognized. As a result, the time period until the firstdecision can be made dependent on when an object would enter the glareregion with a residence probability. Even in the case where no luminousobject is recognizable, it is possible to determine a probability of anobject being situated outside the monitoring region of the monitoringunit, but in the glare region of the headlight. This is advantageousparticularly if the visual range of the monitoring device is so low thatit is smaller than the glare region of the headlight or correspondsthereto. It is therefore additionally advantageous if the residenceprobability outside, but near, the glare region of the headlight is alsodetermined.

In this case, the glare region and the glare distance are described ordefined in this way: the glare region is the region in which glare canbe effected, wherein the boundary of the glare region corresponds to theglare distance in the respective emission direction. In this case, theglare region and the glare distance can be determined depending on thecurrent driving of the headlight, that is to say on the current lightdistribution of the headlight. In this case, the glare distance is themaximum distance at which a glare intensity is generated in the eye ofanother road user, in particular of an oncoming motor vehicle or motorvehicle travelling ahead. Outside the glare region, that is to saybehind the glare distance, is therefore where the intensity is below aglare or threshold value.

The glare region can also be defined by way of the glare perception: theglare perception is significantly reduced outside the glare region incomparison with the glare region.

In this case, the glare intensity is described or defined in this way:the glare intensity is a threshold value below which a reasonable glareeffect for another road user is generated in the eye. The glare effect,that is to say a glare perception, here is highly individual, however,and is dependent both on the surroundings and on the person, inparticular on age.

It is possible to define a threshold value for the glare intensity,wherein this can be carried out even without the individuality. In thiscase, the glare effect increases continuously as the intensityincreases. When a slight glare effect is still acceptable, starting froma higher intensity it is perceived as significantly disturbing. This ismanifested for example in squinting. If the intensity is increasedfurther beyond that, this leads to measurable restrictions of visionand, particularly when lasers are used, may possibly even lead topermanent damage in the eye. In the case of a measurable restriction ofvision, the visual function, particularly in direct proximity to theglare source, is restricted by the blurring effect. This effect can bemeasured, depending on the intensity of the glare source, in a specificscene by means of the equivalent blur luminance. In this case, for thescene without a glare source the blurring effect of the eye is simulatedand the visibility of adjacent objects, that is to say objects situatedin the blur circle, is compared with a visibility given the presence ofa glare source with a specific intensity. In this way, the thresholdvalue for the restrictions of vision can be detected at leaststatistically. For this purpose, it suffices if the threshold value isdefined at least such that no restrictions of vision arise for a healthydriver, Other experts are of the opinion that no driver, regardless ofage, should be expected to put up with a disturbing glare effect. Wherethis threshold value is correspondingly defined depends here on variousfactors that take account of, for example, legislation or the valuepresettings of the automobile manufacturer. A rather defensive thresholdvalue may be assumed for example with a value of 0.05 lux.

The reduction of the glare distance 5 of the at least one headlightleads to a reduction of the glare region. This is effected for exampleby a targeted reduction of the intensity of the light of the headlight.Alternatively or additionally, the angle of the at least one headlightelement can be altered.

It is particularly advantageous here if this reduction is effectedspatially inhomogeneously and a corresponding suppression of glare canbe effected.

FIGS. 2 and 3 show in this respect a light distribution 10, 11 of amotor vehicle comprising, for example, two headlights. The lightdistribution 10 represents an intensity distribution on an area or inthe space in front of the motor vehicle, wherein only a high-beam lightdistribution is discernible. The light distribution 11 represents anintensity distribution on an area or in the space in front of the motorvehicle, wherein a high-intensity beam (high-intensity spot) was addedto the high-beam light distribution, such that the high-beam lightdistribution 10 was supplemented by an almost needlelike intensityextension 12.

The intensity of the light of the headlight can be reduced in apredefined areal or spatial region, such that the glare distance isreduced in a predefined areal or spatial region, in particular in frontof a motor vehicle. In this case, for example, the high-beam lightdistribution or else the high-intensity beam can be reduced in order toreduce the sum of both light intensities.

In accordance with the method according to the invention, the residenceprobability of the luminous object 7, 8 outside the monitoring region 9and within the glare region 20 is determined. In this case, theresidence probability of the luminous object 7, 8 is determined on thebasis of the data of the monitoring device or additionally oralternatively of the other sensor system and/or memory data. On thebasis of the data, in particular image data, an evaluation can becarried out which has the effect that the object can be estimated. If acertain type of object is present for example with a specificprobability, then on the basis of the image data its distance can beestimated and the residence probability can be estimated.

It is advantageous here if the residence probability of the luminousobject is composed of the probability of the luminous object being anobject at risk of glare and/or the probability of the object at risk ofglare being situated in the glare region of the headlight and/or theprobability of an object being present.

The residence probability is determined on the basis of the image dataof the monitoring device. In this case, a plurality of images are takeninto consideration. It is advantageous here to begin with thedetermination of the residence probability as soon as a luminous objectcan be recognized. This is possible particularly in the illuminationregion of the headlight, wherein the illumination region is composed ofthe monitoring region, the glare region and a region in front of theglare region in which no glare takes place. By the time the objectenters the glare region, that is to say for example after a predefinedtime period has elapsed, a first decision must be taken, which affectsthe driving of the headlight. Afterward, the object is tracked furtherin the image data and, if necessary, a second decision is taken, whichaffects the driving of the headlight. It is advantageous here toassociate the type of driving of the headlight with the variation in theimage. In order to be able to better assess the object, therefore, inparticular advantageously during the reduction of the glare region, thatis to say in particular during the reduction of the intensity of thelight of the headlight, the intensity profile of the light of the objectis used for classifying the object. In this case, the reduction of theintensity of the light can be carried out in such a way that it is atleast virtually not recognized by the human eye.

In this case, FIG. 4 shows the actual brightness profile, top in FIG. 4,and the brightness perceived by the human eye, bottom in FIG. 4. In thiscase, the intensity of the reduction can be minimized in such a way thatit is not perceptible or is at least scarcely still perceptible to theeye. This exploits the fact that the eye perceives brightnessdifferences logarithmically. The brightness therefore has to be alteredexponentially in order to bring about an optically uniform variationimpression. In contrast thereto, the light intensity decreases only inproportion to the square of the distance, such that an unnoticedreduction of the light already makes it possible to achieve asuppression of glare for other road users. It is advantageous here if asuppression of glare is effected in the direct surroundings of aluminous object, since the perception of the eye in said surroundings,in a manner similar to that in the case of glare, is restricted by theso-called blur luminance. As a result, the change in brightness isperceived even less in the darker region directly around a luminousobject compared with other regions. On account of this fact, the reducedperceptibility is reinforced again in addition to the effect of thelogarithmic brightness perception of the eye.

FIGS. 5 to 8 show various light distributions of a motor vehicle 50.FIG. 5 shows a low-beam light distribution 51 in the region of theroadway. The light distribution has a small spatial extent and causes noglare for oncoming traffic. The glare distance 55 is small relative tothe spatial extent of the light distribution in the case of the low beamby virtue of the fact that the light beam is directed downward towardthe road. FIG. 6 shows a high-beam light distribution 52 in the regionof the roadway. This light distribution is generated by a matrixheadlight, for example. The light distribution already has a greaterspatial extent and thus a glare distance 56. FIG. 7 shows a high-beamlight distribution 52 in the region of the roadway and a high-intensitybeam 53. The latter is generated by a laser-based headlight illuminant,for example. The light distribution of the in particular laser-basedhigh-intensity beam 53 alone, that is to say with the high-beam lightdistribution 52 switched off, has an even greater spatial extent andthus an even greater glare distance 57. FIG. 8 shows the superimpositionof the light distribution of the high beam 52 and of the high-intensitybeam 53 to form a resulting light distribution 54 having an even greaterglare distance 58.

In this case, the glare region of the headlight can be divided forexample into a safe zone and into a comfort zone, wherein no damage tothe eye and no serious visual restrictions are present in the safe zoneand no glare effect is present in the comfort zone. If an object is thenrecognized, the reduction of the glare region in the case of residenceprobabilities below a threshold value, such as a safety zone thresholdvalue, can be effected in such a way that the object is situated atleast in the safe zone. Advantageously, the reduction can also beeffected in such a way that the object is situated in the comfort zone.This can in particular also be done depending on a second thresholdvalue, such as a comfort zone threshold value.

For strategic reasons it is advantageous if in the case of an unsafedistance determination for the object, the glare region of the headlightis reduced in such a way that all objects are situated at least in asafe zone.

According to the invention, the light intensity can be reduced in aregion having increased brightness compared with the surroundingdistribution.

Moreover, the reduction of the light intensity is achieved by reducingor switching off superimposing light sources or light distributionswhich are used for generating a matrix high beam and/or which lie in theregion in which additional spotlights are superimposed on the matrixhigh beam and/or lie in a region centrally with respect to the matrixhigh beam.

FIGS. 9 to 11 show situations in which a method according to theinvention is carried out.

FIG. 9 shows a light distribution in accordance with FIG. 8 in which ata great distance an object 100, such as a non-classified ornon-classifiable object 100, appears and enters the glare region of thelight distribution 54. Said object is recognized as a luminous object bythe monitoring device, see left-hand illustration in FIG. 9. Even if theobject was possibly already recognized as a luminous object by themonitoring device before entering the glare region, nevertheless it wasnot able to be recognized as a road user with sufficient certaintywithin a predefined time period. As a result, it is not ensured that theobject is identifiable as a road user by the time it enters the glareregion. It can therefore be assumed that the object is possibly a roaduser situated outside the monitoring region of the camera but alreadywithin the glare region of the headlight. The low-beam is subsequentlyreduced in terms of its range or glare distance, such that the resultinglight distribution 59 has a reduced glare distance 60. Optionally,before the dimming, a residence probability can be determined in anintermediate step on the basis of the classification result. Thedetermination of the residence probability reveals, for example, thatthere is a 50% probability of the object being a motor vehicle which,under the assumption that it is a motor vehicle, is situated in theglare region of the headlight with a probability of 70%. Both values lieabove the threshold values of for example 40% and 50%, respectively.Alternatively, it is possible to determine a conditional probability andto compare it with only one threshold value. Possibly, the value of themost probable distance of the potential motor vehicle is furthermoredetermined.

The reduction of the glare distance here advantageously involvesreducing the light distribution 52 of the matrix high beam in the region65 superimposed by the light distribution of the spot region of ahigh-intensity beam 53, such as a laser beam, in particular. In thiscase, the glare distance 58 is reduced to a glare distance 60 of theresulting cumulative light distribution 59 depending on the degree ofthe reduction of the intensity of the matrix high beam. The total lightdistribution is designated by 61. The glare region 60 can therefore bereduced relative to the glare region 58 to any distance, down to therange of the light distribution of the high-intensity beam 53, such as alaser beam, depending on what and whether an intensity of the adaptedlight distribution of the matrix high beam is still superimposed withthe light distribution 53. It is particularly advantageous here if thematrix headlight reduces the region superimposed by the high-intensitybeam, such as the laser beam, continuously or in a stepwise manner inorder that the reduction is not perceived as disturbing by the driver.Furthermore, it is advantageous if the intensity of the matrix high beamis reduced in such a way that the new glare region is no longer outsidethe monitoring region. Alternatively, it is advantageous if the matrixhigh beam is reduced depending on the latitude of the residenceprobability and/or depending on the most probable distance of thepotential motor vehicle. Furthermore, it is advantageous if the glaredistance of the laser spot does not lie outside the monitoring range.Since the motor vehicle 50 is travelling, the object 100, that is to saythe potential motor vehicle, is coming relatively closer.

FIG. 10 shows a light distribution 59 in accordance with FIG. 9,right-hand illustration. In the case of a reduction of the illuminationof the headlight, a reduction of the light intensity of the object 100is recognized, which indicates a reflector as object 100. As a result ofthis observation, the object 100, although it is situated outside themonitoring region of the monitoring unit, can then be identified withhigh certainty as an object for which glare does not have to besuppressed. It can therefore be illuminated maximally again. Arebrightening and thus a reducing of the reduction is the consequence.This can be effected in particular by a stepwise or continuous increasein the intensity of the light distribution of the matrix light in theregion of the laser beam, such that the rebrightening is not perceivedas disturbing by the driver. If the object 100 is already identified asan object for which glare does not have to be suppressed with highcertainty during the reduction of the headlight, then it is advantageousto interrupt said reduction and directly to begin the rebrightening. Inthis case, it is furthermore advantageous only to effect brightening iffurther luminous objects within the maximum glare region are no longerrecognized or supposed. Advantageously, therefore, brightening should beeffected only if no (further) objects are present with a residenceprobability greater than a predefined threshold value. If this isensured, the light distribution 54 in accordance with FIG. 8 issubsequently generated again.

FIG. 11, left-hand illustration, shows a light distribution 59 inaccordance with FIG. 9, right-hand illustration. Upon a reduction of theillumination of the headlight, in this case no reduction of the lightintensity of the object 100 is recognized, which indicates aself-luminous object 100, that is to say for example an oncoming motorvehicle as object 100. As a result of this observation, the object 100,although it is situated outside the monitoring region of the monitoringunit, can then be identified with high certainty as an object for whichglare is to be suppressed. The reduction of the glare distance istherefore maintained. The object is coming relatively closer, as shownin the middle and right-hand illustrations in FIG. 11. In FIG. 11, left,the suppression of glare is effected if possible by the furthersuppression of glare of the high beam in accordance with the objectdistance. As the object comes nearer, such that it enters the glaredistance of the high-intensity beam, the reduction of the matrix highbeam in the region superimposed by the laser spot no longer suffices forsuppression of glare. Therefore, the suppression of glare for the objectis effected by the suppression of glare of the high-intensity beam andby deactivation of the high-intensity beam (laser spot) withsimultaneous reactivation of the matrix high beam in the superimposedregion, see FIG. 11, middle. As the object comes ever closer still, thesuppression of glare for the object is effected with a deactivatedhigh-intensity beam and by conventional (renewed) suppression of glareof the high beam in the near region. The high beam is cropped in termsof its light distribution by darkening 70 of an areal or spatial region,advantageously of the spatial region in which the motor vehicle issituated.

In this case an object is deemed to be non-classifiable if theclassification method yields no result or yields no result withsufficient quality or yields no result in a predefined time period orthe classification method yields no result by the time a predefineddistance of the object is undershot, in particular without—on account ofa driving of the headlight—an extended classification being madepossible on the basis of the observation of the effects of the headlightdriving on the object, or if a method for preclassification yields noresult or yields no result with sufficiently good quality.

LIST OF REFERENCE SIGNS

-   1 First light distribution-   2 Second light distribution-   3 Glare distance-   4 Motor vehicle-   5 Glare distance-   6 Road user not yet subjected to glare-   7 Road user or luminous object-   8 Traffic signs or luminous object-   9 Monitoring region-   10 Light distribution-   11 Light distribution-   12 Intensity extension-   20 Glare region-   50 Motor vehicle-   51 Low-beam light distribution-   52 High-beam light distribution-   53 High-intensity beam-   54 Light distribution-   55 Glare distance-   56 Glare distance-   57 Glare distance-   58 Glare distance-   59 Light distribution-   60 Glare distance-   61 Total light distribution-   65 Superimposed region-   70 Darkening-   100 Object

The invention claimed is:
 1. Method for controlling a light distributionof a headlight, in particular of a headlight comprising one illuminantor comprising a plurality of illuminants which generates or generate anadaptable light distribution, wherein a glare region of the lightdistribution is defined with a glare distance outside which no causingof glare for a road user is effected, wherein an optical monitoringdevice having a monitoring region having a monitoring boundary isprovided, wherein a luminous object is identifiable as a road user onlywithin the monitoring region, wherein upon recognition or supposition ofat least one luminous object which is outside the monitoring region butwithin the glare region, the at least one headlight is driven such thatthe glare distance is adapted, such as in particular reduced.
 2. Methodaccording to claim 1, wherein the glare distance is reduced if the glareregion is set to be larger than the monitoring region, in particular ifthe glare region corresponds to the maximum glare region.
 3. Methodaccording to claim 1, wherein the glare distance remains unchanged or isincreased if the glare region is set to be smaller than the monitoringregion or in a manner corresponding to the monitoring region.
 4. Methodaccording to claim 1, wherein the adaptation, such as in particular thereduction, of the glare distance of the at least one headlight iseffected on the basis of a residence probability of the luminous object.5. Method according to claim 1, wherein for reducing the glare regionand/or the glare distance, the intensity of the light of the headlightis reduced.
 6. Method according to claim 5, wherein the intensity of thelight of the headlight is reduced in a predefined areal or spatialregion, such that the glare distance is reduced in a predefined areal orspatial region, in particular in front of a motor vehicle.
 7. Methodaccording to claim 4, wherein the residence probability of the luminousobject outside the monitoring region and within the glare region isdetermined.
 8. Method according to claim 4, wherein the residenceprobability of the luminous object is determined on the basis of thedata of the monitoring device.
 9. Method according to claim 8, whereinthe residence probability of the luminous object is composed of theprobability of the luminous object being an object at risk of glare orbeing assumed to be such and/or the probability of the object at risk ofglare being situated in the glare region or in the illumination regionof the headlight and/or the probability of an object being present. 10.Method according to claim 9, wherein the illumination region is composedof the monitoring region, the glare region and a region in front of theglare region in which no glare takes place.
 11. Method according toclaim 1, wherein during the reduction of the intensity of the light ofthe headlight, the intensity profile of the light of the object is usedfor classifying the object.
 12. Method for controlling a lightdistribution of a headlight, in particular of a headlight comprising oneilluminant or comprising a plurality of illuminants which generates orgenerate an adaptable light distribution, wherein a glare region of thelight distribution is defined with a glare distance outside which nocausing of glare for a road user is effected, wherein an opticalmonitoring device having a monitoring region having a monitoringboundary is provided, wherein an object is identifiable as a road useronly within the monitoring region, wherein upon recognition of an objectwhich might be a road user or upon supposition of a road user, whichobject or which road user is outside the monitoring region but withinthe glare region, the at least one headlight is driven such that theglare distance is reduced.
 13. Method according to claim 12, wherein theresidence probability of a recognized object and/or of a supposed roaduser outside the monitoring region and within the glare region isdetermined.
 14. Method according to claim 1, wherein the glare region ofthe headlight is divided into a safe zone and into a comfort zone,wherein no damage to the eye and no serious visual restrictions arepresent in the safe zone and no glare effect is present in the comfortzone.
 15. Method according to claim 1, wherein the reduction of theglare region in the case of residence probabilities below a thresholdvalue is effected in such a way that the object is situated at least inthe safe zone.
 16. Method according to claim 1, wherein the reductiongiven the presence of a residence probability above a threshold value iseffected in such a way that the object is situated at least in thecomfort zone.
 17. Method according to claim 1, wherein in the case of anunsafe distance determination for the object, the glare region of theheadlight is reduced in such a way that all objects are situated atleast in a safe zone.
 18. Method according to claim 1, wherein the lightintensity is reduced in a region having increased brightness comparedwith the surrounding distribution.
 19. Method according to claim 1,wherein the reduction of the light intensity is achieved by reducing orswitching off superimposing light sources or light distributions whichare used for generating a matrix high beam and/or which lie in theregion in which at least one spotlight or spotlights is or areadditionally superimposed on the matrix high beam and/or lies or lie ina region centrally with respect to the matrix high beam.
 20. Methodaccording to claim 1, wherein an object is regarded as not classifiableor as not identifiable as a road user if the classification methodyields no result or yields no result with sufficient quality or yieldsno result in a predefined time period or the classification methodyields no result by the time a predefined distance of the object isundershot, or if a method for preclassification yields no result oryields no result with sufficiently good quality.
 21. Method according toclaim 1, wherein the illumination region is extended if the probabilityof an object at risk of glare being situated outside the monitoringregion decreases or becomes zero or falls below a threshold value. 22.Method according to claim 1, wherein the reduction of the lightdistribution is reversed by the superimposing light distribution beingswitched on again, in particular switched on in a stepwise manner. 23.Method according to claim 1, wherein the glare region or theillumination zone is reduced given the presence of a glare probability,wherein the glare region or the illumination zone is reduced orshortened when objects are present outside the classification range,and/or the glare region or the illumination zone is reduced or shortenedwhen non-classifiable objects are present, and/or the glare region orthe illumination zone is reduced or shortened when non-visible regionsare detected.
 24. Motor vehicle comprising at least one headlight,advantageously comprising two headlights, and comprising an opticalmonitoring device for carrying out a method of claim 1.